如图所示，一通电螺旋线管的右端为北极（N）极，且它的右侧有一小磁针，请你在图中标出小磁针的南极（S）及用箭头标出螺线管中的电流I的方向

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比一比，再组词。

歇____      莺____       嗓____      桶____      句____

喝____      英____       澡 ____      痛____      甸____

根据短文内容和中文提示，写出空白处各单词的正确形式。

    Dreams make life more colorful. ____ (几乎) everyone wants to have a ____ (更好) life. Me, too. I have ____ (数个) dreams. I'm looking forward to ____ (完成)my study and finding a good job. I am ____ (确定)I will enjoy ____ (我) at work. ____(在…期间) the holidays, I will go to the park to help collect ____ (垃圾). I want to do it because I always ____ (担心) about our living place. It's too dirty. I ____ (希望) everybody will do something to make our earth beautiful.

设$a={\int }_0^{\mathrm{\pi }}\left(\cos x-\sin x\right)dx$，则二项式${\left(x^2+\frac{a}{x}\right)}^6$展开式中的$x^3$项的系数为(    )